Shell roofing



S. H. G. ATKINS SHELL ROOFING April 12, 1955 5 Shets-Sheet 1 Filed July 11, 1952 S. H. G. ATKINS SHELL ROOFING April 12, 1955 5 Sheets-Sheet 2 Filed July 11, 1952 Avmswroe 6% @W-% A rive/v5 Y April 12, 1955 s. H. e. ATKINS SHELL ROOFING 5 Sheets-Sheet 3 Filed July 11, 1952 .N l um H H HMH H MHHWI MH Wllllllllllllllllllllllllllllllllll HUM April 12, 1955 s. H. s. ATKINS 2,705,929

SHELL ROOFING Filed July 11, 1952 5 Sheets-Sheet 4 April 1955 s. H. e. ATKINS 2.705,.929

SHELL ROOFING Filed July 11, 1952 5 Sheets-Sheet 5 United States Patent SHELL ROOFING Stanley Henry George Atkins, London, England, assignor to R. E. Eagan Limited, London, England, a British company Application July 11, 1952, Serial No. 298,397

Claims priority, application Great Britain July 13, 1951 12 Claims. (Cl. 108-1) This invention relates to shell roofing of all shapes, such as barrel roofing, domes and north light roofing. The object of the invention is the provision of improvements in such roofing, and the invention consists broadly in making such roofing of precast concrete units.

In order that the invention shall be the more clearly understood a number of embodiments thereof will now be described, reference being made to the accompanying drawings wherein:

Figure 1 is a sectional elevation of a roof structure in accordance with the invention, the section being on line I-I of Figure 2;

Figure 2 is a sectional elevation of the same with the section taken in a plane at right angles to that of Figure 1, the section being on line IIII of Figure 1;

Figure 3 is a sectional elevation, to a larger scale then that of Figures 1 and 2, of one of the precast concrete units constituting the roof, the section being taken on line III-1H of Figure 4;

Figure 4 is a sectional elevation of the same unit, the section being taken on line IVIV of Figure 3;

Figure 5 is a portion of an outside elevation of the same unit looking from the right of Figure 4;

Figure 6 is a sectional elevation of a portion of the same unit, the section being on line VIVI of Figure 3;

Figure 7 is an outside elevation of the roof structure of Figures 1 and 2 viewed from the right of Figure 1;

Figure 8 is a view to a larger scale of a portion of the left hand unit of Figure 7;

Figure 9 isa similar view to Figure 8 of the unit adjacent to that of Figure 8;

Figure 10 is a similar view to those of Figures 8 and 9 of any one of the centre units of Figure 7;

Figure 11 is a view, similar to that of Figure 3, illustrating a modification;

Figure 12 is a sectional elevation to a reduced scale showing a way in which the structure of Figure 1 can b modified;

Figure 13 is a sectional elevation on line X[II-XIII of Figure 14 showing a further modification;

Figure 14 is a plan of the same;

Figure 15 is a sectional elevation of a portion of a roof structure, of the so-called north light type, according to the invention;

Figure 16 is a section on line XVI--XVI of Figure Figure 17 is a sectional elevation showing a further modification of the invention, the section being on line XVIIXVII of Figure 18;

Figure 18 is a side elevation of the same looking from the left of Figure 17.

Referring first to Figures 1 to 10, this illustrates the invention as applied to barrel roofing, i. e. shell roofing approximating to part cylindrical form and having its lower edges at the same level. In the structure illustrated in Figures 1, 2 and 7, the roofing consists of a plurality of contiguous parallel spans of barrel roofing,

but there could of course be only a single one of such 2,705,929 Patented Apr. 12, 1955 secured together by means of bolts passing through these bolt holes.

Each unit is formed with thickened portions 4 at its side edges so that the barrel roof as a whole is formed with edge beams. These thickened portions 4 are cast with holes 5, 6 and 7 which register so that through holes are provided extending from end to end of the edge beams. Reinforcement is provided in these through holes after the units are assembled in situ. In the particular construction illustrated it will be seen that the holes 5 provide a straight horizontal duct at the bottom of the edge beam, and that the holes 6 and 7 provide rather narrower ducts above the duct 5 which are not straight but have a downward sag. The duct 5 is intended to receive a straight mild steel bar which is subsequently put in tension and grouted in. The ducts 6 and 7 are intended to receive post tensioning wires which are also preferably grouted in. It will be appreciated that other forms of reinforcement may be preferred. For example the mild steel bar may be dispensed with and one or more post tensioning wires alone relied on, or individual lengths of reinforcement may be cast into the edge beam portions 4 of the individual units, and asteel bar passed from end to end through the edge beam, as a whole.

The units are cast so that grouting spaces 8 are formed at the edge junctions between them, so that when the grouting spaces are filled in said edge junctions are completely weather proof.

During erection, the end barrel units 1 are placed on their permanent supports, while the interior barrel units rest on temporary supports. The vertical flanges or ribs 2, which may be made in such a way as to transmit the vertical and horizontal shear from one unit to another are then bolted together. The grouting between the units is then made.

The main longitudinal connecting reinforcement is then applied to the edge beam portion 4 of the units and the temporary supports for the interior units may then be removed.

In the structure of Figures 1 and 2 it will be seen that the end supports are constituted by walls 9 and that tlhe ends of the barrel roofing spans are bricked in as at Referring to Figure 11 this shows a unit 1 in which one or more window openings 11 are cast in the unit.

Instead of barrel units being employed, each of which extends from one side to the other of a barrel roofing span, we may employ units of half width, each of which extends from one side of the barrel roofing span to the crown, the pairs of half-width units being joined at the crown by bolting together downwardly depending vertical longitudinal flanges cast with the units, which flanges or ribs can be much less deep than the end flanges or ribs 2 heretofore described. Grouting spaces would also be provided at these longitudinal junctions.

Referring to Figure 12 this shows a construction in which, instead of the spans of barrel roofing being contiguous as in Figures 1, 2 and 7, they alternate with spans of flat roofing between them. The spans of flat roofing are constituted by units 12. These units 12 rest on the edge beams 4 of the units 1 as clearly shown. Said units may be of about the same length as the units 1 and may have end flanges 13 whereby they are bolted together in the same manner as the units 1. The bending moment applied to each span of units 12 is of course taken by the reinforced edge beams 4 of the units 1.

Referring now to Figures 13 and 14, these figures illustrate a roof structure consisting, as in the case of Figures 1, 2 and 7, of a number of contiguous spans of barrel roofing. In the case, however, of Figures 13 and 14 each span of barrel roofing is made up of side units 14 each of which comprises one edge beam portion 4 but extends less than half way across to the edge beam portion 4 at the other side. Thus each span of barrel roofing is divided at its crown by a gap which extends throughout the full length of said span. This gap is bridged by means of cross bars 15 which thus unite the barrel roofing span into an integral whole.

For securing the cross bars 15 to the units 14, each of said units 14 is formed with a downwardly extending flange 16 along its longitudinal edge opposite to the edge beam portion 4. The cross bars 15 have holes through them from one end to the other, and they are bolted between the adjacent flanges 16 by means of bolts, each passing through one of said cross bars and through both flan es.

It will be understood that the units 14, like the units 1, have flanges 2 at their end edges which enable said units 14 to be connected together end to end in the same way as the units 1. The edge beams 4 are of course reinforced as before. Transparent window panes are 1nserted between the cross bars 15, and it will be seen that continuous roof lights are provided extending from end to end of each span of barrel roofing.

Referring to Figures 15 and 16, these figures illustrate an embodiment of the invention as applied to north light roof structures, that is roof structures which comprise a long horizontal row of windows (usually facing north and slightly inclined to the vertical), and a convexly curved shell roof extending from the upper edge of said row of windows to a line level with and behind the lower edge. In this case, each span of north light roofing comprises a series of precast concrete shell roof units 17 connected together end to end to form the complete span of sheet roof. The edges of said unit 17 ad acent the upper edge of the row of windows are supported by struts 18 and the window panes 19 are located between said struts 18. The shell roof units 17 are formed with vertical flanges or ribs 2 at their end edges by which they are bolted to each other in the same manner as the units 1 and they are also formed at their bottom edges with thickened edge beam portions 4 which together provide an edge beam for the shell roof. Said edge beam portions 4 may be connected together and reinforced according to any of the ways described in connection with the edge beam units of the barrel roof.

In the particular construction illustrated in Figures 15 and 16, there are a plurality of contiguous parallel spans of north light roofing, and the struts 18 of each span have their lower ends supported on a rail constituted by upturned tail portions 20 of the units of the ad acent span, which tail portions extend rearwardly and upwardly from the edge beam portions 4 of said units of the adjacent span as clearly shown.

Referring now to Figures 17 and 18, these figures illustrate an embodiment of the invention as applied to wing roofing for protecting passengers on a railway platform. In this case a plurality of columns 21 are mounted on the platform 22 at spaced intervals of about fifty feet along the centre line of the platform, and these columns support two continuous wing roof spans which in cross section extend one each side, each on a more-or-less part cylindrical curve upwardly and outwardly from the upper ends of said columns.

In the present arrangement each of these continuous shell roof spans is constituted by a series of precast units 23 secured together end to end. The units at their end edges are cast with flanges 2, and the flanges of adjacent units are bolted together in the same way as the units 1 and 17 of the preceding embodiments. The units at their lower edges are formed with thickened edge beam portions 4 which, as in the preceding embodiments, together form an edge beam, and each of the edge beams is reinforced in the same manner as in the preceding embodiments. Thus there are two edge beams side by side resting on the columns 21 and the two shell roof spans (as seen in cross section) curve upwardly and outwardly from the respective edge beams. The two edge beams may be secured to each other and to the columns 21 in any suitable way.

The invention can also be applied to domes. In the case of a dome there could be four units each consisting of a quarter dome. The units would be cast with inwardly extending vertical flanges or ribs at their contacting edges and would be secured together by means of bolts passing through said flanges or ribs. The units would also be formed to provide a thickened ring round the bottom edge of the dome, in which ring tensioning reinforcing wire would be provided.

It will be seen that by this invention we provide for shell roofing in which in situ concrete work and costly curved shuttering are eliminated on the site, and the speed of erection is greatly increased. Moreover, as a complete shell is composed of a number of identical precast units, only one mould unit need be made. Thus it becomes economical to make this mould the ideal shape or curve (i. e. not limiting it to a circular curve as usual).

Also the precasting results in better concrete and better finish.

I claim:

1. A span of shell roofing constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of the span, each of said units being curved in a sense laterally of the span with its concave side upwards, and being formed with a thickened portion, and the thickened portions together forming a continuous beam extending longitudinally of the span, and reinforcement extending longitudinally through said continuous beam and tying said units together, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

2. A span of shell roofing constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of the span, each of said units being curved in a sense laterally of the span with its concave side upwards, and being formed with thickened portions along each of its lower edges, and the thickened portions together forming two continuous beams extending longitudinally of the span, and reinforcement extending longitudinally through said continuous beams and tying said units together, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

3. A shell roofing comprising a plurality of spans of shell roofing arranged in spaced relationship parallel side by side, each of said spans being constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of the span, each of said units being curved in a sense laterally of the span with its concave side upwards and being formed with thickened portions along each of its lower edges, and the thickened portions together forming two continuous beams extending longitudinally of the span, and reinforcement extending longitudinally through said continuous beams and tying said units together, whereby said span is capable of withstanding bending moment with said reinforcement in tension, and additional roofing filling in the spaces between said plurality of spans, said additional roofing being supported between adjacent continuous beams of said spans.

4. A span of barrel roofing having continuous window space along the crown thereof, the half of said span on each side of said window space being constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of the span, each of sald units being formed with a thickened portion along ts lower edge, and the thickened portions together form- 111g a continuous beam extending longitudinally of the span, and reinforcement extending longitudinally through said cotinuous beam whereby said half of said span is capable of withstanding bending moment with said reinforcement in tension, and cross members bridging said wlndow space and coupling said two halves of said span.

5. A span of barrel roofing having continuous window space along the crown thereof, the half of said span on each side of said window space being constituted by a plurahty of shell units of precast concrete assembled together to form a series longitudinally of the span and reinforcement extending longitudinally through said units adjacent their lower edges whereby said half of said span 1s capable of withstanding bending moment with said re nforcement in tension, and cross members bridging said window space and coupling said two halves of said span.

6. A span of barrel roofing constituted by a plurality of shell un ts of precast concrete assembled together to form a series longitudinally of said span, and reinforcement extending longitudinally through said units on each side of said span adjacent the lower edges of said units, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

7. A span of shell roofing which is curved in cross section with its convex face outwards and which has one longitudinal edge at a higher level than the other, and strut members supporting said higher level edge to provide window space, said span of shell roofing being constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of said span, and reinforcement extending longitudinally through said units adjacent their lower edges, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

8. A span of shell roofing which is curved in cross section with its convex face outwards and which has one longitudinal edge at a higher level than the other, and strut members supporting said higher level edge to provide Window space, said span of shell roofing being constituted by a plurality of shell units of precast concrete assembled together to form a series longitudinally of said span, each unit being formed with a thickened portion along its lower edge and the thickened portions together forming a continuous beam extending longitudinally of the span, and reinforcement extending longitudinally through said continuous beam, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

9. A roofing consisting of a plurality of spans according to claim 7 arranged parallel side by side, the strut members of one span being supported at their lower edges on the shell units of the next span.

10. A span of wing roofing, that is a span of shell roofing with one longitudinal edge higher than the other and unsupported, said span of shell roofing being constituted by a plurality of shell units of precast concrete assembled together to form a series extending longitudinally of the span, and reinforcement extending longitudinally of the span through said units adjacent their lower edge, whereby said span is capable of withstanding bending moment with said reinforcement in tension.

11. A span of wing roofing, that is a span of shell roofing with one longitudinal edge higher than the other and unsupported, said span of shell roofing being constituted by a plurality of shell units of precast concrete assembled together to form a series extending longitudinally of the span, each of said shell units having a thickened portion extending along its lower edge and the thickened portions together forming a continuous beam extending longitudinally of the span, and reinforcement extending longitudinally of said beam whereby said span is capable of withstanding bending moment with said reinforcement in tension.

12. A roofing consisting of two spans of wing roofing according to claim 11, said spans being arranged with their continuous beams contiguous and their upper unsupported edges pointing away from one another.

References Cited in the file of this patent UNITED STATES PATENTS 862,292 Stofier Aug. 6, 1907 1,144,200 Hewett June 22, 1915 2,102,447 Whitacre Dec. 14, 1937 2,387,487 Abeles Oct. 23, 1945 FOREIGN PATENTS 548,021 Great Britain of 1942 

